As shown in patent document 1, a prior 3-level power converter includes a DC voltage source having a positive terminal, an intermediate terminal, and a negative terminal, first and second IGBT sequentially connected in series between the positive terminal and an AC output terminal, a first coupling diode connected between a connection point between the first and second IGBT and the intermediate terminal, third and fourth IGBT sequentially connected in series between the AC output terminal and the negative terminal, and a second coupling diode connected between a connection point between the third and fourth IGBT and the intermediate terminal, and the power converter is configured to appropriately perform on/off control of the first to fourth IGBT so as to output a 3-level voltage from the AC output terminal.
Patent document 1: Japanese Patent No. 3,229,931